[The restoration by Escherichia coli RecA protein of the survival of gamma-irradiated HeLa cells reduced by the DNA repair inhibitors caffeine and 3-aminobenzamide]

Abstract

It is confirmed that inhibitors of DNA repair caffeine and 3-aminobenzamide decrease the survival of gamma-irradiated HeLa cells. It is shown that the decreased survival of irradiated cells is reversed when Escherichia coli RecA protein is introduced into cell nucleases with the aid of liposomes. This effect is more expressed in caffeine-treated (before or after irradiation) than in 3-aminobenzamide-treated (before irradiation) cells. It is suggested that E. coli 38 kD RecA protein may compensate the function of HeLa RecA-like protein, inhibited by DNA repair inhibitors, which is necessary for the repair of single-strand breaks and double-strand breaks of DNA.